Contrast agent-enhanced magnetic resonance imaging of tissue perfusion

Abstract

This invention relates to a method of contrast agent-enhanced magnetic resonance imaging of perfusion in vasculated tissue within a human or non-human animal body in which a bolus comprising a contrast-enhancing amount of a magnetic resonance imaging contrast agent is administered into the vascular system of said body, and said body is subjected to a magnetic resonance imaging procedure whereby signals or images representative of first pass of said contrast agent bolus through tissue of interest are generated, characterised in that (i) said contrast agent is capable of exhibiting simultaneous, determinable T 1 and T 2 * reducing effects under the imaging procedure employed and (ii) a T 1 -weighted imaging procedure is used (a) to visualise the first pass of said contrast agent bolus through said tissue by virtue of its signal lowering T 2 * effect and (b) to obtain a T 1 -weighted contrast agent-enhanced image of said tissue.

What is claimed is:  
     
       1. A method of contrast agent-enhanced magnetic resonance imaging of perfusion in vasculated tissue within a human or non-human animal body in which a bolus comprising a contrast-enhancing amount of a magnetic resonance imaging contrast agent is administered into the vascular system of said body, and said body is subjected to a magnetic resonance imaging procedure whereby signals or images representative of first pass of said contrast agent bolus through tissue of interest are generated, characterised in that (i) said contrast agent exhibits simultaneous, determinable T 1  and T 2 * reducing effects under the imaging procedure employed and (ii) a T 1 -weighted imaging procedure is used (a) to visualise the first pass of said contrast agent bolus through said tissue by virtue of its signal lowering T 2 * effect and (b) to obtain a T 1 -weighted contrast agent-enhanced image of said tissue. 
     
     
       2. A method as claimed in  claim 1  wherein said contrast agent has a magnetic moment greater than 1000 Bohr Magnetons. 
     
     
       3. A method as claimed in  claim 1  wherein said contrast agent has a magnetic moment greater than 5000 Bohr Magnetons. 
     
     
       4. A method as claimed in  claim 1  wherein said contrast agent has a r 2 /r 1  ratio of less than 3, measured at 0.5 T and 40° C., where r 1  , and r 2  are the T 1  and T 2  relaxivities respectively. 
     
     
       5. A method as claimed in  claim 4  wherein said ratio is less than 2. 
     
     
       6. A method as claimed  claim 1  wherein said contrast agent has an r, value of at least 10 mM −1 s −1 , measured at 0.5 T and 40° C., where r 1  and r 2  are the T 1  and T 2  relaxivities respectively. 
     
     
       7. A method as claimed in  claim 6  wherein said r 1  value is at least 15 mM −1 l s −1 . 
     
     
       8. A method as claimed in  claim 1  wherein said bolus administration involves injection of a 1-10 ml volume of a contrast medium comprising said contrast agent and wherein said injection lasts 1-5 secs.